A current model transmission electron microscope (TEM) is requested for use in a central campus multi-user facility. The TEMs presently being used were both purchased in the l96Os, and have become inadequate for our present needs. They do not provide some of the functions required by some of the major users. Repair and maintenance have become severe problems, with disruptive "down-time" a common occurrence. The need for an efficient multi-user instrument has become particularly urgent due to a significant recent increase in the number of researchers in a variety of Departments on campus now employing TEM in their research. The requested model TEM, a JEM 1010, has the required functions that our present TEMs lack -specimen tilt, high contrast, minimum dose system - as well as a number of desired improvements in image quality and manipulation. The user-friendliness of the TEM makes it suitable as an efficient multi-user instrument; it would be housed in a new EM suite in the newly-constructed Institute for Molecular and Cellular Biology building, and thus be available as a central campus facility. Given their unreliability alone, neither of the present TEMs would be suitable for this facility. Centralization of our EM facility will optimize our resources, such as technical personnel, and provide better access to TBM for researchers from Departments that do not have a TEM. The requested grant is for just over half of the cost of the TEM; Indiana University will pay for the balance, as well as for a full service contract and the salary of a full-time EM technician. The user group is made up of ten different research labs in five different Departments. The NIH-funded projects that would use the new TEM involve the study of: (i) Cellular processes in photoreceptors; (ii) Control of microtubule function in development; (iii) Mechanisms and functions of subcellular motility; (iv) Analysis of protein kinase C's role in learning in Hermissenda; (v) Neurogenesis in Drosophila; (vi) Protein kinase C in photoreceptors; (vii) Steroids and trophic factors in an aging neuromuscular system; and (viii) Radiation repair and meiosis in Coprinus. Two projects for which NIH funding is being sought are: (i) Control of asymmetry in cell division during development; and (ii) Ocular toxicity studies involving the corneal epithelium.